This invention relates to stabilizer jacks, and in particular, to motorized stabilizer jacks for recreational vehicles adapted to raise a recreational vehicle relative to its suspension to provide stability to the vehicle when parked.
It is desirable to stabilize recreational vehicles once the vehicle is parked for use. A wide variety of recreational vehicle stabilizing jacks have been developed for use in stabilizing recreational vehicles, trailers, and the like, when parked. Prior art jacks raise the vehicle relative to its suspension system thereby preventing rocking and swaying of the recreational vehicle as an occupant moves around in the vehicle. Early stabilizing jacks provided on recreational vehicles were manually operated, requiring the owner to walk around the vehicle and manually operate four jacks to stabilize the vehicle at a campsite. This operation may be difficult and cumbersome, especially at night or in adverse weather conditions.
Later prior art stabilizer jacks were motorized, but still had problems. The motors used were often prone to damage during transport of the recreational vehicle because of clearance problems. Other motorized jacks operated each leg independently making it difficult to properly stabilize the vehicle. U.S. Pat. No. 6,224,102 to Nebel discloses a motorized stabilizer jack utilizing a single drive screw with left and right hand threads with a drive unit mounted to the end of the screw drive. During terrain compensation of this device, the drive screw is forced to move left to right on the body of the recreational vehicle. Mounting the motor on the end of the drive screw creates one of two problems. In the first condition, if the motor is mounted inside the body of the recreational vehicle, the amount of screw available for use is limited, causing the stabilizer legs to be closer together under the vehicle. In a second alternative condition, the motor is mounted outside of the body of the recreational vehicle. When maneuvering in tight areas such as camp grounds, the motor can be damaged, as well as the vehicle itself, because of trees and rocks. U.S. Pat. No. 5,826,889 to Eden utilized a vertical screw drive that is rotated in position at the time of use. The space required to operate such a system is not always available under the recreational vehicle thereby limiting its functionality.
In view of the foregoing disadvantages inherent in the known types of devices now present in the prior art, the present invention has as its main objective to provide a motorized stabilizer jack that has a low profile and fits under a recreational vehicle in a small area without protruding parts. A further objective is to provide a motorized stabilizer jack able to position the stabilizer to the furthest outside edge of the recreational vehicle body thereby providing enhanced stability.
To attain this, the present invention provides a motor driven slip differential which drives a left and a right thread screw lowering stabilizer legs which adjust and compensate for uneven terrain at the same time. The present invention slip differential system has torque balancing properties across two shafts. This allows complete terrain compensation through the entire stroke of the two stabilizers without the need for a balancing electric circuit. The present invention shafts and the drive screw are mounted horizontally making the present invention the only known low profile motor driven under chassis assembly. The present invention""s center drive system creates a beam style support allowing the stabilizer legs to be moved further out for greater stability.
These together with other objects of the invention, along with various features of novelty which characterize the invention, are pointed out with particularity in the claims annexed hereto and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be made to the accompanying drawings and descriptive matter in which there is illustrated a preferred embodiment of the invention.